1. Field of the Invention
The present invention relates to a control device for assisting driving of a vehicle, and more particularly to a control device assisting manipulation of a driver when the driver wants to move a vehicle by a small distance at an intersection of poor visibility or the like.
2. Description of the Background Art
Various types of systems for assisting manipulation of a driver have been developed, which include, for example, a cruise control system having a speed keeping assist function, a driving assist system having a speed keeping assist function, an inter-vehicle distance keeping assist function and a lane keeping assist function, and a parking assist system for easier parking. These systems can reduce the driver's manipulation burden and at the same time improve safety.
Meanwhile, the driver may want to move the vehicle by a small distance, for example if visibility is poor when exiting from a narrow road onto a wide road, or to pass over a step provided on a pallet of a multistory parking garage.
Japanese Patent Laying-Open No. 09-048263 discloses a driving force control device for a vehicle that enables automatic movement of a vehicle by a small distance, to reduce the burden of a driver and improve safety. The driving force control device for a vehicle is for moving a vehicle having a throttle actuator by a distance desired by a driver. The device includes input means for a driver to input a desired moving distance, throttle control means for causing a throttle opening to be input to the throttle actuator, actual travel distance detecting means for detecting an actual travel distance of the vehicle, and braking force generating means for stopping the vehicle when the detected signal of the actual travel distance detecting means reaches the target moving distance.
In this driving force control device for a vehicle, when the driver inputs a desired moving distance via the input means, the moving distance is reported to the throttle control means and to the braking force generating means. The throttle control means causes a throttle opening to be input to the throttle actuator. Here, the throttle control means gradually increases the throttle opening until the vehicle starts moving with reference to the detected value of the actual travel distance detecting means. When the vehicle starts moving, the actual travel distance detecting means reports the actual travel distance of the vehicle to the throttle control means and to the braking force generating means. When the actual travel distance of the vehicle reaches the moving distance input via the input means, the throttle control means inputs to the throttle actuator a command value designating complete closing of a throttle valve. At the same time, the braking force generating means generates the braking force to stop the vehicle.
With the driving force control device for a vehicle disclosed in Japanese Patent Laying-Open No. 09-048263, however, the driver needs to input a desired moving distance. It means that the driver's manipulation burden would not actually be reduced at the blind intersection of poor visibility or on the pallet of the multistory parking garage as described above if the driver does not know how to decide the distance to be input as the desired moving distance.